Amiodarone: clinical trials

Amiodarone is an antiarrhythmic agent commonly used in the treatment of sup raventricular and ventricular tachyarrhythmias. This article reviews the re sults and clinical implications of primary and secondary prevention trials in which amiodarone was used in one of the treatment arms. Key post-myocard ial infarction primary prevention trials include the European Myocardial In farct Amiodarone Trial (EMIAT) and the Canadian Amiodarone Myocardial Infar ction Trial (CAMIAT), both of which demonstrated that amiodarone reduced ar rhythmic but not overall mortality. In congestive heart failure patients, a miodarone was studied as a primary prevention strategy in two pivotal trial s: Grupo de Estudio de ta Sobrevida en la Insuficiencia Cardiac en Argentin a (GESICA) and Amiodarone in Patients With Congestive Heart Failure and Asy mptomatic Ventricular Arrhythmia (CHF-STAT). Amiodarone was associated with a neutral overall survival and a trend toward improved survival in nonisch emic cardiomyopathy patients in CHF/STAT and improved survival in GESICA. I n post-myocardial infarction patients with nonsustained ventricular tachyca rdia and a depressed ejection fraction, the Multicenter Automatic Defibrill ator implantation Trial (MADIT) demonstrated that implantabte cardioverter- defibrillators (ICD) statistically improved survival compared to the antiar rhythmic drug arm, most of whose patients were taking amiodarone. In patien ts with histories of sustained Ventricular tachycardia or ventricular fibri llation, the Cardiac Arrest Study in Seattle: Conventional Versus Amiodaron e Drug Evaluation (CASCADE) trial demonstrated that empiric amiodarone lowe red arrhythmic recurrence rates compared to other drugs guided by serial Ho lter or electrophysiologic studies. However, arrhythmic death rates were hi gh in both treatment arms of the study. Several secondary prevention trials , including the Antiarrhythmics Versus Implantable Defibrillators Study (AV ID), the Canadian Implantable Defibrillator Study (CIDS), and the Cardiac A rrest Study Hamburg (CASH), have demonstrated the superiority of ICD therap y compared to empiric amiodarone in improving overall survival. Based on th e above findings, amiodarone is safe to use in post-myocardial infarction a nd congestive heart failure patients that need antiarrhythmic therapy. Alth ough amiodarone is effective in treating malignant arrhythmias, high-risk p atients should be considered for an ICD as frontline therapy. Curr Opin Car diol 2000, 15:64-72 (C) 2000 Lippincott Williams & Wilkins, Inc.